Sewage Sludge

Introduction

Sludge
originates from the process of treatment of waste water. Due to
the physical-chemical processes involved in the treatment, the sludge
tends to concentrate heavy metals and poorly biodegradable trace
organic compounds as well as potentially pathogenic organisms (viruses,
bacteria etc) present in waste waters. Sludge is, however, rich
in nutrients such as nitrogen and phosphorous and contains valuable
organic matter that is useful when soils are depleted or subject
to erosion. The organic matter and nutrients are the two main elements
that make the spreading of this kind of waste on land as a fertiliser
or an organic soil improver suitable.

The progressive implementation of the Urban Waste
Water Treatment Directive
91/271/EEC in all Member States is increasing the quantities
of sewage sludge requiring disposal. From an annual production of
some 5.5 million tonnes of dry matter in 1992, the Community is
heading towards nearly 9 million tonnes by the end of 2005. This
increase is mainly due to the practical implementation of the Directive
as well as the slow but constant rise in the number of households
connected to sewers and the increase in the level of treatment (up
to tertiary treatment with removal of nutrients in some Member States).
The Directive sets the following targets for secondary treatment
of waste waters coming from agglomerations:

at the latest by 31 December 2000 for agglomerations of more
than 15,000 p.e. (population equivalent);

at the latest by 31 December 2005 for agglomerations between
10,000 and 15,000 p.e.;

at the latest by 31 December 2005 for agglomerations of between
2,000 and 10,000 p.e. discharging to fresh waters and estuaries.

There are more stringent provisions for agglomerations
discharging into sensitive areas such as fresh waters or estuaries.

The Sewage Sludge Directive
86/278/EEC seeks to encourage the use of sewage sludge in agriculture
and to regulate its use in such a way as to prevent harmful effects
on soil, vegetation, animals and man. To this end, it prohibits
the use of untreated sludge on agricultural land unless it is injected
or incorporated into the soil. Treated sludge is defined as having
undergone "biological, chemical or heat treatment, long-term
storage or any other appropriate process so as significantly to
reduce its fermentability and the health hazards resulting from
its use". To provide protection against potential health risks
from residual pathogens, sludge must not be applied to soil in which
fruit and vegetable crops are growing or grown, or less than ten
months before fruit and vegetable crops are to be harvested. Grazing
animals must not be allowed access to grassland or forage land less
than three weeks after the application of sludge. The Directive
also requires that sludge should be used in such a way that account
is taken of the nutrient requirements of plants and that the quality
of the soil and of the surface and groundwater is not impaired.

The Directive specifies rules for the sampling
and analysis of sludges and soils. It sets out requirements for
the keeping of detailed records of the quantities of sludge produced,
the quantities used in agriculture, the composition and properties
of the sludge, the type of treatment and the sites where the sludge
is used. Limit values for concentrations of heavy metals in sewage
sludge intended for agricultural use and in sludge-treated soils
are in Annexes I A, I B and I C of the Directive.

Although at Community level the reuse of sludge
accounts for about 40% of the overall sludge production, landfilling
as well as incineration in some Member States are the most widely
used disposal outlets despite their environmental drawbacks.
(last updated 12.9.2002)

Revision of the Sewage Sludge Directive

Directive 86/278/ EEC was adopted over 20 years ago with a view to encourage the application of sewage sludge in agriculture and to regulate its use, so as to present harmful effects on soil, vegetation, animals and humans.

The European Commission is currently assessing whether the current Directive should be reviewed – and if so, the extent of this review. For example, Directive 86/278/EEC sets limit values for seven heavy metals. Since its adoption, several Member States have enacted and implemented stricter limit values for heavy metals and set requirements for other contaminants.

For its assessment, the European Commission has launched a study to gather existing information on the environmental, economic, and social as well as health impacts of present practices of sewage sludge use on land. This study will also assess the risks and opportunities that can be foreseen in coming years. The study identified possible options for European policy and estimated their costs and benefits. The Commission has chosen the consultancy team of Milieu Ltd, WRc PLC and RPA Ltd to undertake this study.

Public Consultations

Two online consultations has conducted for the project.

First round has been addressed to stakeholders who registered for consultation and has been closed on 10 August. The second round has been closed on 29 January 2010.

All deliverables and comments may be found at dedicated CIRCA website.
New documents added to CIRCA on 15 October 2010 - "working document on sludge and bio-waste"

In the context of the revision process of the Sewage Sludge Directive it has been found that further information are urgently needed about the presence of emerging pollutants in the sewage sludge which could contaminate terrestrial and aquatic environment when the sludge is used in agriculture. Therefore the Commission has dedicated one of the FATE series monitoring projects (monitoring of the fate and impact of pollutants on the terrestrial/aquatic interface) to the sewage sludge. The goal of this exercise is to gain an European-wide snapshot on the occurrence and concentration levels of "classical" inorganic and organic contaminants such as heavy metals, PCBs, PCDD/Fs, and PAHs, but also on less investigated emerging compounds such as, for instance, brominated flame retardants, ingredients of personal care products, pharmaceuticals, some industrial chemicals, etc. in sewage sludge (FATE SEES) and treated bio-waste (FATE COMES).

The DG ENV together with DG JRC has organized a workshop summarizing the results of FATE-SEES component which had place in Brussels on 6 June 2012. The presentation of results was followed by presentation of some Member States experience when setting limits for contaminants in sewage sludge.